sp.h

sp.h is a single-header C and C++ library implementing a thin, cross-platform API for subprocess management, with no external dependencies, targeting Windows and POSIX systems.

The library focuses on direct process execution and I/O redirection without relying on shells, external tools, or platform-specific wrappers.

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Project integration

sp.h is a single-header library, so integrating it into your project is straight-forward. Drop the header file into your project tree and, in exactly one of your translation units, define SP_IMPLEMENTATION before including it:

#define SP_IMPLEMENTATION
#include "sp.h"

This causes sp.h to emit its function definitions into that translation unit. In all other files that include sp.h, only the public API declarations are visible.

This works for both C and C++ translation units.

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Example

#define SP_IMPLEMENTATION
#include "sp.h"

int main(void)
{
    SpCmd cmd = {0}; // In C++, use {} for initialization

    sp_cmd_add_arg(&cmd, "echo");
    sp_cmd_add_arg(&cmd, "hello");

    int exit_code = sp_cmd_exec_sync(&cmd);

    sp_cmd_free(&cmd);

	return exit_code;
}

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Logging and diagnostics

By default, sp.h performs no logging and produces no stdout/stderr output of its own. All informational and error messages are disabled unless explicitly enabled by the user.

Logging can be enabled by defining the following macros before including sp.h, in the same translation unit as you define SP_IMPLEMENTATION:

#define SP_LOG_INFO(msg)  printf("%s\n", (msg)) // Or your logging function of choice
#define SP_LOG_ERROR(msg) fprintf(stderr, "Error: %s\n", (msg)) // Or your logging function of choice

These macros are invoked by sp.h when commands are executed or when errors occur. msg is a NUL-terminated C-string.

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Non-goals

sp.h intentionally keeps its scope small. It does not aim to provide:

• Shell parsing or command-line interpretation
• Job control, terminal emulation, or signal forwarding
• High-level process orchestration or pipelines
• Environment-variable management beyond inheritance

The goal is to expose a minimal, predictable subprocess API that maps closely to native platform behavior.

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Tested platforms and compilers

Linux

• Compilers: GCC 14, Clang 20
• C standards: C99, C11, C17, C23
• C++ standards: C++11, C++14, C++17, C++20, C++23, C++26
• Flags: -Wall -Wextra -Werror -pedantic-errors

Windows

• Compiler: MSVC 2022 (cl)
• C standards: C11, C17
• C++ standards: C++14, C++17, C++20, C++latest
• Flags: /W4 /WX

macOS

• Compiler: Apple Clang (latest)
• C standards: C99, C11, C17, C2x
• C++ standards: C++11, C++14, C++17, C++20, C++2b
• Flags: -Wall -Wextra -Werror -pedantic-errors

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License

sp.h is licensed under the 3-Clause BSD license. See the LICENSE file for details.