The stat() system call in POSIX C returns file metadata—including file size, inode number, permission bits, block allocation count, ownership UIDs, and access timestamps—from a file's inode structure without opening or reading the file contents. The struct stat data structure The system header <sys/stat.h> defines the struct stat layout. Complete C code example Pass a filename path to stat() and parse st_mode bitmasks using standard S_IFMT macros.

Architecture and Core Concepts

Compile and run Gotchas: stat vs lstat vs fstat stat() follows symbolic links - stat() resolves symlinks to target files. To inspect the symlink file itself without following it, use lstat() . fstat() operates on open file descriptors - if you already have an open file descriptor ( int fd ), use fstat(fd, &sb) to avoid extra path lookup operations. The stat() system call retrieves file types, permission masks, and inode details without reading target file content.

Gotchas and Troubleshooting Checklist

  • Permission & Access Control - verify user privilege level (sudo access or file ownership) before running commands.

  • Environment & Path Resolution - confirm environment variables and binary PATH entries match target software releases.

  • Log Diagnostics - inspect relevant system logs or application trace outputs to verify clean execution.

Following these steps provides a clean, reliable, and production-ready solution for inspect file attributes in c using the stat system call.