C語言獲取進程可執行文件路徑：跨平台方案 (Linux/proc、Windows API、macOS)

Linux: /proc 文件系統

#include <unistd.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>

char *get_exe_path_linux(char *buf, size_t size) {
    ssize_t len = readlink("/proc/self/exe", buf, size - 1);
    if (len != -1) {
        buf[len] = '\0';
        return buf;
    }
    return NULL;
}

Windows: GetModuleFileNameW

#include <windows.h>
#include <stdio.h>
#include <stdlib.h>

char *get_exe_path_windows(char *buf, size_t size) {
    wchar_t wbuf[MAX_PATH];
    DWORD len = GetModuleFileNameW(NULL, wbuf, MAX_PATH);
    if (len == 0 || len == MAX_PATH) return NULL; // 截斷或失敗
    // WideCharToMultiByte 轉 UTF-8
    int n = WideCharToMultiByte(CP_UTF8, 0, wbuf, len, buf, (int)size, NULL, NULL);
    if (n == 0) return NULL;
    buf[n] = '\0';
    return buf;
}

macOS: _NSGetExecutablePath

#include <mach-o/dyld.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>

char *get_exe_path_macos(char *buf, size_t size) {
    uint32_t bufsize = (uint32_t)size;
    if (_NSGetExecutablePath(buf, &bufsize) == 0) {
        // 解析符號鏈接獲取真實路徑
        char realpath_buf[PATH_MAX];
        if (realpath(buf, realpath_buf)) {
            snprintf(buf, size, "%s", realpath_buf);
            return buf;
        }
        return buf;
    }
    return NULL; // 緩衝區太小，bufsize 返回所需大小
}

跨平台封裝範例

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#if defined(_WIN32) || defined(_WIN64)
  #include <windows.h>
  #define GET_EXE_IMPL get_exe_path_windows
#elif defined(__APPLE__)
  #include <mach-o/dyld.h>
  #include <limits.h>
  #define GET_EXE_IMPL get_exe_path_macos
#else
  #include <unistd.h>
  #include <limits.h>
  #define GET_EXE_IMPL get_exe_path_linux
#endif

char *get_executable_path(char *buf, size_t size) {
    return GET_EXE_IMPL(buf, size);
}

int main() {
    char path[4096];
    if (get_executable_path(path, sizeof(path))) {
        printf("Executable: %s\n", path);
    } else {
        fprintf(stderr, "Failed to get executable path\n");
        return 1;
    }
    return 0;
}

注意事項

• 緩衝區大小建議 ≥ `PATH_MAX` (通常 4096)。
• Windows `MAX_PATH` (260) 限制可通過 `\\?\` 前綴或 `GetModuleFileNameW` 大緩衝區繞過。
• Linux `/proc/self/exe` 為符號鏈接，`readlink` 直接讀取目標。
• macOS `_NSGetExecutablePath` 可能返回相對路徑，需 `realpath` 規範化。