lib.detect

This module provides very powerful probing capabilities for probing programs, compilers, language features, dependencies, and more.

NOTE

The interface of this module is spread across multiple module directories, try to import it by importing a single interface, which is more efficient.

detect.find_file

Find files

This interface provides a more powerful project than os.files, which can specify multiple search directories at the same time, and can also specify additional subdirectories for each directory to match the pattern lookup, which is equivalent to an enhanced version of os.files.

E.g:

lua

import("lib.detect.find_file")

local file = find_file("ccache", { "/usr/bin", "/usr/local/bin"})

If found, the result returned is: /usr/bin/ccache

It also supports pattern matching paths for recursive lookups, similar to os.files:

lua

local file = find_file("test.h", { "/usr/include", "/usr/local/include/**"})

Not only that, but the path inside also supports built-in variables to get the path from the environment variables and the registry to find:

lua

local file = find_file("xxx.h", { "$(env PATH)", "$(reg HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\XXXX;Name)"})

If the path rules are more complex, you can also dynamically generate path entries through a custom script:

lua

local file = find_file("xxx.h", { "$(env PATH)", function () return val("HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\XXXX;Name"):match ("\"(.-)\"") end})

In most cases, the above use has met various needs. If you need some extended functions, you can customize some optional configurations by passing in the third parameter, for example:

lua

local file = find_file("test.h", { "/usr", "/usr/local"}, {suffixes = {"/include", "/lib"}})

By specifying a list of suffixes subdirectories, you can extend the list of paths (the second parameter) so that the actual search directory is expanded to:

/usr/include
/usr/lib
/usr/local/include
/usr/local/lib

And without changing the path list, you can dynamically switch subdirectories to search for files.

NOTE

We can also quickly call and test this interface with the xmake lua plugin: xmake lua lib.detect.find_file test.h /usr/local

detect.find_path

Find the path

The usage of this interface is similar to lib.detect.find_file, the only difference is that the returned results are different. After the interface finds the incoming file path, it returns the corresponding search path, not the file path itself. It is generally used to find the parent directory location corresponding to the file.

lua

import("lib.detect.find_path")

local p = find_path("include/test.h", { "/usr", "/usr/local"})

If the above code is successful, it returns: /usr/local, if test.h is in /usr/local/include/test.h.

Another difference is that this interface is passed in not only the file path, but also the directory path to find:

lua

local p = find_path("lib/xxx", { "$(env PATH)", "$(reg HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\XXXX;Name)"})

Again, this interface also supports pattern matching and suffix subdirectories:

lua

local p = find_path("include/*.h", { "/usr", "/usr/local/**"}, {suffixes = "/subdir"})

detect.find_library

Find library files

This interface is used to find library files (static libraries, dynamic libraries) in the specified search directory, for example:

lua

import("lib.detect.find_library")

local library = find_library("crypto", {"/usr/lib", "/usr/local/lib"})

Running on macosx, the results returned are as follows:

lua

{
    filename = libcrypto.dylib
,   linkdir = /usr/lib
,   link = crypto
,   kind = shared
}

If you do not specify whether you need a static library or a dynamic library, then this interface will automatically select an existing library (either a static library or a dynamic library) to return.

If you need to force the library type you need to find, you can specify the kind parameter as (static/shared):

lua

local library = find_library("crypto", {"/usr/lib", "/usr/local/lib"}, {kind = "static"})

This interface also supports suffixes suffix subdirectory search and pattern matching operations:

lua

local library = find_library("cryp*", {"/usr", "/usr/local"}, {suffixes = "/lib"})

detect.find_program

Find executable programs

This interface is more primitive than lib.detect.find_tool, looking for executables through the specified parameter directory.

lua

import("lib.detect.find_program")

local program = find_program("ccache")

The above code is like not passing the search directory, so it will try to execute the specified program directly. If it runs ok, it will return directly: ccache, indicating that the search is successful.

Specify the search directory and modify the test command parameters that are attempted to run (default: ccache --version):

lua

localProgram = find_program("ccache", {paths = {"/usr/bin", "/usr/local/bin"}, check = "--help"})

The above code will try to run: /usr/bin/ccache --help, if it runs successfully, it returns: /usr/bin/ccache.

If --help can't satisfy the requirement, some programs don't have the --version/--help parameter, then you can customize the run script to run the test:

lua

local program = find_program("ccache", {paths = {"/usr/bin", "/usr/local/bin"}, check = function (program) os.run("%s -h", program) end })

Similarly, the search path list supports built-in variables and custom scripts:

lua

local program = find_program("ccache", {paths = {"$(env PATH)", "$(reg HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\AeDebug;Debugger)"}})
local program = find_program("ccache", {paths = {"$(env PATH)", function () return "/usr/local/bin" end}})

NOTE

In order to speed up the efficiency of frequent lookups, this interface comes with a default cache, so even if you frequently find the same program, it will not take too much time. If you want to disable the cache, you can clear the local cache by executing xmake f -c in the project directory.

We can also test quickly with xmake lua lib.detect.find_program ccache.

detect.find_programver

Find the executable version number

lua

import("lib.detect.find_programver")

local programver = find_programver("ccache")

The return result is: 3.2.2

By default it will try to get the version via ccache --version. If this parameter doesn't exist, you can specify other parameters yourself:

lua

local version = find_programver("ccache", {command = "-v"})

Even the custom version gets the script:

lua

local version = find_programver("ccache", {command = function () return os.iorun("ccache --version") end})

For the extraction rule of the version number, if the built-in matching mode does not meet the requirements, you can also customize:

lua

local version = find_programver("ccache", {command = "--version", parse = "(%d+%.?%d*%.?%d*.-)%s"})
local version = find_programver("ccache", {command = "--version", parse = function (output) return output:match("(%d+%.?%d*%.?%d*.-)%s ") end})

NOTE

In order to speed up the efficiency of frequent lookups, this interface is self-contained by default. If you want to disable the cache, you can execute xmake f -c in the project directory to clear the local cache.

We can also test quickly with xmake lua lib.detect.find_programver ccache.

detect.find_package

Find package files

After 2.6.x this interface is not recommended for direct use (internal use only), for library integration, please use add_requires() and add_packages() as much as possible.

detect.find_tool

Find tool

This interface is also used to find executable programs, but more advanced than lib.detect.find_program, the function is also more powerful, it encapsulates the executable program, providing the concept of tools:

toolname: tool name, short for executable program, used to mark a
tool, for example: gcc, clang, etc. program: executable program
command, for example: xcrun -sdk macosx clang

The corresponding relationship is as follows:

toolname	program
clang	`xcrun -sdk macosx clang`
gcc	`/usr/toolchains/bin/arm-linux-gcc`
link	`link.exe -lib`

lib.detect.find_program can only determine whether the program exists by passing in the original program command or path. And find_tool can find the tool through a more consistent toolname, and return the corresponding program complete command path, for example:

lua

import("lib.detect.find_tool")

local tool = find_tool("clang")

The result returned is: {name = "clang", program = "clang"}, at this time there is no difference, we can manually specify the executable command:

lua

local tool = find_tool("clang", {program = "xcrun -sdk macosx clang"})

The result returned is: {name = "clang", program = "xcrun -sdk macosx clang"}

In macosx, gcc is clang. If we execute gcc --version, we can see that it is a vest of clang. We can intelligently identify it through the find_tool interface:

lua

local tool = find_tool("gcc")

The result returned is: {name = "clang", program = "gcc"}

The difference can be seen by this result. The tool name will actually be marked as clang, but the executable command uses gcc.

We can also specify the {version = true} parameter to get the version of the tool, and specify a custom search path. It also supports built-in variables and custom scripts:

lua

local tool = find_tool("clang", {version = true, paths = {"/usr/bin", "/usr/local/bin", "$(env PATH)", function () return "/usr/xxx/bin" end}})

The result returned is: {name = "clang", program = "/usr/bin/clang", version = "4.0"}

This interface is a high-level wrapper around find_program, so it also supports custom script detection:

lua

local tool = find_tool("clang", {check = "--help"})
local tool = find_tool("clang", {check = function (tool) os.run("%s -h", tool) end})

Finally, the search process of find_tool:

First try to run and detect with the argument of {program = "xxx"}. 2. If there is a detect.tools.find_xxx script in xmake/modules/detect/tools, call this script for more accurate detection. 3. Try to detect from the system directory such as /usr/bin, /usr/local/bin.

We can also add a custom lookup script to the module directory specified by add_moduledirs in the project xmake.lua to improve the detection mechanism:

projectdir
- xmake/modules
- detect/tools/find_xxx.lua

For example, we customize a lookup script for find_7z.lua:

lua

import("lib.detect.find_program")
import("lib.detect.find_programver")

function main(opt)

    -- init options
    opt = opt or {}

    -- find program
    local program = find_program(opt.program or "7z", opt.pathes, opt.check or "--help")

    -- find program version
    local version = nil
    if program and opt and opt.version then
        version = find_programver(program, "--help", "(%d+%.?%d*)%s")
    end

    -- ok?
    return program, version
end

After placing it in the project's module directory, execute: xmake l lib.detect.find_tool 7z to find it.

NOTE

We can also test quickly with xmake lua lib.detect.find_tool clang.

detect.find_toolname

Find tool name

Match the corresponding tool name with the program command, for example:

program	toolname
`xcrun -sdk macosx clang`	clang
`/usr/bin/arm-linux-gcc`	gcc
`link.exe -lib`	link
`gcc-5`	gcc
`arm-android-clang++`	clangxx
`pkg-config`	pkg_config

Compared with program, toolname can uniquely mark a tool, and it is also convenient to find and load the corresponding script find_xxx.lua.

detect.find_cudadevices

Find CUDA devices of the host

Enumerate CUDA devices through the CUDA Runtime API and query theirs properties.

lua

import("lib.detect.find_cudadevices")

local devices = find_cudadevices({ skip_compute_mode_prohibited = true })
local devices = find_cudadevices({ min_sm_arch = 35, order_by_flops = true })

The result returned is: { { ['$id'] = 0, name = "GeForce GTX 960M", major = 5, minor = 0, ... }, ... }

The included properties will vary depending on the current CUDA version. Please refer to CUDA Toolkit Documentation and its historical version for more information.

detect.features

Get all the features of the specified tool

This interface is similar to compiler.features. The difference is that this interface is more primitive. The passed argument is the actual tool name toolname.

And this interface not only can get the characteristics of the compiler, the characteristics of any tool can be obtained, so it is more versatile.

lua

import("lib.detect.features")

local features = features("clang")
local features = features("clang", {flags = "-O0", program = "xcrun -sdk macosx clang"})
local features = features("clang", {flags = {"-g", "-O0", "-std=c++11"}})

By passing in flags, you can change the result of the feature, for example, some features of C++11, which are not available by default. After enabling -std=c++11, you can get it.

A list of all compiler features can be found at compiler.features.

detect.has_features

Determine if the specified feature is supported

This interface is similar to compiler.has_features, but more primitive, the passed argument is the actual tool name toolname.

And this interface can not only judge the characteristics of the compiler, but the characteristics of any tool can be judged, so it is more versatile.

lua

import("lib.detect.has_features")

local features = has_features("clang", "cxx_constexpr")
local features = has_features("clang", {"cxx_constexpr", "c_static_assert"}, {flags = {"-g", "-O0"}, program = "xcrun -sdk macosx clang"})
local features = has_features("clang", {"cxx_constexpr", "c_static_assert"}, {flags = "-g"})

If the specified feature list exists, the actual supported feature sublist is returned. If none is supported, nil is returned. We can also change the feature acquisition rule by specifying flags.

A list of all compiler features can be found at compiler.features.

detect.has_flags

Determine if the specified parameter option is supported

This interface is similar to compiler.has_flags, but more primitive, the passed argument is the actual tool name toolname.

lua

import("lib.detect.has_flags")

local ok = has_flags("clang", "-g")
local ok = has_flags("clang", {"-g", "-O0"}, {program = "xcrun -sdk macosx clang"})
local ok = has_flags("clang", "-g -O0", {toolkind = "cxx"})

Returns true if the test passed.

The detection of this interface has been optimized. Except for the cache mechanism, in most cases, the tool's option list (--help) will be directly judged. If the option list is not available, it will be tried. The way to run to detect.

detect.has_cfuncs

Determine if the specified c function exists

This interface is a simplified version of lib.detect.check_cxsnippets and is only used to detect functions.

lua

import("lib.detect.has_cfuncs")

local ok = has_cfuncs("setjmp")
local ok = has_cfuncs({"sigsetjmp((void*)0, 0)", "setjmp"}, {includes = "setjmp.h"})

The rules for describing functions are as follows:

Function Description	Description
`sigsetjmp`	pure function name
`sigsetjmp((void*)0, 0)`	Function Call
`sigsetjmp{int a = 0; sigsetjmp((void*)a, a);}`	function name + {} block

In the last optional parameter, in addition to specifying includes, you can also specify other parameters to control the option conditions for compile detection:

lua

{ verbose = false, target = [target|option], includes = .., configs = {linkdirs = .., links = .., defines = ..}}

The verbose is used to echo the detection information, the target is used to append the configuration information in the target before the detection, and the config is used to customize the compilation options related to the target.

detect.has_cxxfuncs

Determine if the specified c++ function exists

This interface is similar to lib.detect.has_cfuncs, please refer to its instructions for use. The only difference is that this interface is used to detect c++ functions.

detect.has_cincludes

Determine if the specified c header file exists

This interface is a simplified version of lib.detect.check_cxsnippets and is only used to detect header files.

lua

import("lib.detect.has_cincludes")

local ok = has_cincludes("stdio.h")
local ok = has_cincludes({"stdio.h", "stdlib.h"}, {target = target})
local ok = has_cincludes({"stdio.h", "stdlib.h"}, {configs = {defines = "_GNU_SOURCE=1", languages = "cxx11"}})

detect.has_cxxincludes

Determine if the specified c++ header file exists

This interface is similar to lib.detect.has_cincludess, please refer to its instructions for use. The only difference is that this interface is used to detect c++ header files.

detect.has_ctypes

Determine if the specified c type exists

This interface is a simplified version of lib.detect.check_cxsnippets and is only used to detect functions.

lua

import("lib.detect.has_ctypes")

local ok = has_ctypes("wchar_t")
local ok = has_ctypes({"char", "wchar_t"}, {includes = "stdio.h"})
local ok = has_ctypes("wchar_t", {includes = {"stdio.h", "stdlib.h"}, configs = {"defines = "_GNU_SOURCE=1", languages = "cxx11"}})

detect.has_cxxtypes

Determine if the specified c++ type exists

This interface is similar to lib.detect.has_ctypess. Please refer to its instructions for use. The only difference is that this interface is used to detect c++ types.

detect.check_cxsnippets

Check if the c/c++ code snippet can be compiled

The generic c/c++ code snippet detection interface, by passing in a list of multiple code snippets, it will automatically generate a compiled file, and then common sense to compile it, if the compilation pass returns true.

For some complex compiler features, even if compiler.has_features can't detect it, you can detect it by trying to compile through this interface.

lua

import("lib.detect.check_cxsnippets")

local ok = check_cxsnippets("void test() {}")
local ok = check_cxsnippets({"void test(){}", "#define TEST 1"}, {types = "wchar_t", includes = "stdio.h"})

This interface is a generic version of interfaces such as detect.has_cfuncs, detect.has_cincludes, and detect.has_ctypes, and is also lower level.

So we can use it to detect: types, functions, includes and links, or combine them together to detect.

The first parameter is a list of code fragments, which are generally used for the detection of some custom features. If it is empty, it can only detect the conditions in the optional parameters, for example:

lua

local ok = check_cxsnippets({}, {types = {"wchar_t", "char*"}, includes = "stdio.h", funcs = {"sigsetjmp", "sigsetjmp((void*)0, 0)"} })

The above call will check if the types, includes and funcs are both satisfied, and return true if passed.

There are other optional parameters:

lua

{ verbose = false, target = [target|option], sourcekind = "[cc|cxx]"}

The verbose is used to echo the detection information. The target is used to append the configuration information in the target before the detection. The sourcekind is used to specify the tool type such as the compiler. For example, the incoming cxx is forced to be detected as c++ code.

lib.detect ​

detect.find_file ​

detect.find_path ​

detect.find_library ​

detect.find_program ​

detect.find_programver ​

detect.find_package ​

detect.find_tool ​

detect.find_toolname ​

detect.find_cudadevices ​

detect.features ​

detect.has_features ​

detect.has_flags ​

detect.has_cfuncs ​

detect.has_cxxfuncs ​

detect.has_cincludes ​

detect.has_cxxincludes ​

detect.has_ctypes ​

detect.has_cxxtypes ​

detect.check_cxsnippets ​

lib.detect

detect.find_file

detect.find_path

detect.find_library

detect.find_program

detect.find_programver

detect.find_package

detect.find_tool

detect.find_toolname

detect.find_cudadevices

detect.features

detect.has_features

detect.has_flags

detect.has_cfuncs

detect.has_cxxfuncs

detect.has_cincludes

detect.has_cxxincludes

detect.has_ctypes

detect.has_cxxtypes

detect.check_cxsnippets