Process start

gistfile1.txt

Here's a simple C program that launches calc.exe using the Windows API:

```c
#include <windows.h>

int main() {
    // Use ShellExecute to launch calculator
    HINSTANCE result = ShellExecuteA(NULL, "open", "calc.exe", NULL, NULL, SW_SHOW);
    
    // Check if the execution was successful
    if ((int)result <= 32) {
        // Error occurred
        return 1;
    }
    
    return 0;
}
```

This code:
1. Includes the necessary Windows header
2. Uses `ShellExecuteA` (ANSI version) to launch calc.exe
3. The parameters are:
   - NULL: No window handle needed
   - "open": Operation to perform
   - "calc.exe": File to execute
   - NULL: No parameters
   - NULL: Default directory
   - SW_SHOW: Shows the window normally
4. Checks if the execution was successful (returns > 32 on success)
5. Returns appropriate exit code

To compile this with something like GCC (MinGW):
```
gcc -o calc_launcher calc_launcher.c
```

Alternatively, here's a version using `CreateProcess` which gives more control:

```c
#include <windows.h>

int main() {
    STARTUPINFOA si = {0};
    PROCESS_INFORMATION pi = {0};
    
    // Initialize startup info
    si.cb = sizeof(si);
    
    // Create the process
    BOOL success = CreateProcessA(
        "C:\\Windows\\System32\\calc.exe", // Full path to calculator
        NULL,                             // No command line arguments
        NULL,                             // Process handle not inheritable
        NULL,                             // Thread handle not inheritable
        FALSE,                            // Don't inherit handles
        0,                               // No creation flags
        NULL,                            // Use parent's environment
        NULL,                            // Use parent's directory
        &si,                             // Startup info
        &pi                              // Process info
    );
    
    if (!success) {
        return 1;
    }
    
    // Clean up process and thread handles
    CloseHandle(pi.hProcess);
    CloseHandle(pi.hThread);
    
    return 0;
}
```

Both versions will work on Windows systems. The `ShellExecuteA` version is simpler but less configurable, while the `CreateProcessA` version gives you more control over the process creation but requires more setup.

Note: The actual path to calc.exe might vary depending on your Windows installation (though ShellExecute will usually find it in the system directory automatically).