Methods

Description: Various Methods


 ✓ printf 
 ✓ fprintf - Formatted output to a file stream.
 ✓ sprintf - Formatted output to a string.
 ✓ snprintf - Formatted output to a string with size limit (safer).
 ✓ scanf - Formatted input from stdin.
 ✓ fscanf - Formatted input from a file stream.
 ✓ sscanf - Formatted input from a string.
 ✓ getchar - Read a single character from stdin.
 ✓ putchar - Write a single character to stdout.
 ✓ fgets - Read a line from a file stream (safer than gets).
 ✓ fputs - Write a string to a file stream.
 ✓ fopen - Open a file.
 ✓ fclose - Close a file.
 ✓ fread - Read data from a file.
 ✓ fwrite - Write data to a file.
 ✓ fseek - Reposition file pointer.
 ✓ ftell - Get current file pointer position.
 ✓ rewind - Set file pointer to beginning.
 ✓ perror - Print system error message.
 ✓ feof - Check end-of-file indicator.
 ✓ ferror - Check error indicator.
 ✓ clearerr - Clear error and EOF indicators.
 ✓ fflush - Flush a file stream.


 ° malloc - Allocate memory.
 ° calloc - Allocate and clear memory.
 ° realloc - Resize allocated memory.
 ° free - Deallocate memory.
 ° memcpy - Copy memory area.
 ° memmove - Copy memory area (handles overlapping).
 ° memset - Fill memory with a constant byte.
 ° memcmp - Compare memory areas.
 ° memchr - Search memory for a character.
III. String Manipulation (string.h, stdlib.h)
 ° strcpy - Copy string (unsafe).
 ° strncpy - Copy string with size limit (safer).
 ° strcat - Concatenate strings (unsafe).
 ° strncat - Concatenate strings with size limit (safer).
 ° strcmp - Compare strings.
 ° strncmp - Compare strings with size limit.
 ° strlen - Get string length.
 ° strchr - Find first occurrence of character in string.
 ° strrchr - Find last occurrence of character in string.
 ° strstr - Find first occurrence of substring.
 ° strtok - Tokenize string (not reentrant, problematic).
 ° strtok_r - Reentrant string tokenizer.
 ° strerror - Get error message string.
 ° atoi - Convert string to integer.
 ° atol - Convert string to long integer.
 ° atoll - Convert string to long long integer.
 ° atof - Convert string to double.
 ° strtol - Convert string to long integer with error checking.
 ° strtoul - Convert string to unsigned long integer with error checking.
 ° strtod - Convert string to double with error checking.
IV. Process Control (unistd.h, stdlib.h, sys/wait.h)
 ° fork - Create a new process.
 ° execve - Execute a program.
 ° execl, execv, execle, execvp, execvpe - Variants of exec.
 ° wait - Wait for any child process to terminate.
 ° waitpid - Wait for a specific child process to terminate.
 ° exit - Terminate the current process normally.
 ° _exit - Terminate the current process immediately.
 ° getenv - Get environment variable.
 ° setenv - Set environment variable.
 ° unsetenv - Unset environment variable.
 ° system - Execute a shell command.
 ° getpid - Get process ID.
 ° getppid - Get parent process ID.
 ° sleep - Suspend execution for a specified number of seconds.
 ° usleep - Suspend execution for a specified number of microseconds (deprecated, use nanosleep).
V. File System Operations (unistd.h, sys/stat.h, fcntl.h)
 ° open - Open a file descriptor.
 ° close - Close a file descriptor.
 ° read - Read from a file descriptor.
 ° write - Write to a file descriptor.
 ° lseek - Reposition file descriptor offset.
 ° stat - Get file status.
 ° fstat - Get file status from file descriptor.
 ° lstat - Get file status from symbolic link.
 ° mkdir - Create a directory.
 ° rmdir - Remove a directory.
 ° unlink - Delete a name and possibly the file it refers to.
 ° rename - Change the name or location of a file.
 ° chmod - Change file permissions.
 ° chown - Change file owner and group.


 ∆ time - Get current time as time_t.
 ∆ ctime - Convert time_t to string.
 ∆ gmtime - Convert time_t to UTC tm structure.
 ∆ localtime - Convert time_t to local tm structure.
 ∆ mktime - Convert tm structure to time_t.
 ∆ strftime - Format time into a string.
 ∆ difftime - Compute difference between two time_t values.
VII. Utility & Miscellaneous (stdlib.h, unistd.h, limits.h, etc.)
 ∆ abs, labs, llabs - Absolute value of integer types.
 ∆ rand - Generate a pseudo-random integer.
 ∆ srand - Seed the pseudo-random number generator.
 ∆ qsort - Quicksort array.
 ∆ bsearch - Binary search array.
 ∆ getopt - Parse command-line options.
 ∆ gethostname - Get the name of the current host.
 ∆ sysconf - Get system configuration information.
 ∆ exit - Terminate process (already listed, but important enough to reinforce).
VIII. Concurrency (pthread.h - often linked separately, but core to libc functionality on many systems)
 ∆ pthread_create - Create a new thread.
 ∆ pthread_join - Wait for a thread to terminate.
 ∆ pthread_mutex_init
 ∆ pthread_mutex_lock,  
∆ pthread_mutex_unlock - Basic mutex operations for thread synchronization.