The Linux Manuals (man pages) document is an important part of Linux documents. Linux Manuals are organized as several sections. Each section has a group of commands for a specific area in Linux usage, administration or development.
cacheflush – flush contents of instruction and/or data cache Synopsis#include <asm/cachectl.h> int cacheflush(char *addr, int nbytes, int cache);Note: On some architectures, there is no glibc wrapper for this system call; see NOTES. Descriptioncacheflush() flushes the contents of the indicated cache(s) for the user addresses in the range addr to (addr+nbytes-1). cache may be one of:…
brk, sbrk – change data segment size Synopsis#include <unistd.h> int brk(void *addr); void *sbrk(intptr_t increment); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): brk(), sbrk(): Since glibc 2.19: _DEFAULT_SOURCE || (_XOPEN_SOURCE >= 500) && ! (_POSIX_C_SOURCE >= 200112L)From glibc 2.12 to 2.19: _BSD_SOURCE || _SVID_SOURCE || (_XOPEN_SOURCE >= 500) && ! (_POSIX_C_SOURCE >= 200112L)Before glibc 2.12: _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500Descriptionbrk() and sbrk()…
afs_syscall, break, fattach, fdetach, ftime, getmsg, getpmsg, gtty, isastream, lock, madvise1, mpx, prof, profil, putmsg, putpmsg, security, stty, tuxcall, ulimit, vserver – unimplemented system calls SynopsisUnimplemented system calls. DescriptionThese system calls are not implemented in the Linux kernel. Return ValueThese system calls always return -1 and set errno to ENOSYS. NotesNote that ftime(3), profil(3), and…
bpf – perform a command on an extended BPF map or program Synopsis#include <linux/bpf.h> int bpf(int cmd, union bpf_attr *attr, unsigned int size);DescriptionThe bpf() system call performs a range of operations related to extended Berkeley Packet Filters. Extended BPF (or eBPF) is similar to the original ("classic") BPF (cBPF) used to filter network packets. For…
bdflush – start, flush, or tune buffer-dirty-flush daemon Synopsis#include <sys/kdaemon.h> int bdflush(int func, long *address); int bdflush(int func, long data);DescriptionNote: Since Linux 2.6, this system call is deprecated and does nothing. It is likely to disappear altogether in a future kernel release. Nowadays, the task performed by bdflush() is handled by the kernel pdflush thread….
sync_file_range – sync a file segment with disk Synopsis#define _GNU_SOURCE /* See feature_test_macros(7) */ #include <fcntl.h> int sync_file_range(int fd, off64_t offset, off64_t nbytes, unsigned int flags);Descriptionsync_file_range() permits fine control when synchronizing the open file referred to by the file descriptor fd with disk. offset is the starting byte of the file range to be synchronized….
posix_fadvise – predeclare an access pattern for file data Synopsis#include <fcntl.h> int posix_fadvise(int fd, off_t offset, off_t len, int advice);Feature Test Macro Requirements for glibc (see feature_test_macros(7)): posix_fadvise(): _POSIX_C_SOURCE >= 200112LDescriptionPrograms can use posix_fadvise() to announce an intention to access file data in a specific pattern in the future, thus allowing the kernel to perform appropriate optimizations….
posix_fadvise – predeclare an access pattern for file data Synopsis#include <fcntl.h> int posix_fadvise(int fd, off_t offset, off_t len, int advice);Feature Test Macro Requirements for glibc (see feature_test_macros(7)): posix_fadvise(): _POSIX_C_SOURCE >= 200112LDescriptionPrograms can use posix_fadvise() to announce an intention to access file data in a specific pattern in the future, thus allowing the kernel to perform appropriate optimizations….
arch_prctl – set architecture-specific thread state Synopsis#include <asm/prctl.h> #include <sys/prctl.h> int arch_prctl(int code, unsigned long addr); int arch_prctl(int code, unsigned long *addr);Descriptionarch_prctl() sets architecture-specific process or thread state. code selects a subfunction and passes argument addr to it; addr is interpreted as either an unsigned long for the "set" operations, or as an unsigned long *,…
alloc_hugepages, free_hugepages – allocate or free huge pages Synopsisvoid *alloc_hugepages(int key, void *addr, size_t len, int prot, int flag); int free_hugepages(void *addr);DescriptionThe system calls alloc_hugepages() and free_hugepages() were introduced in Linux 2.5.36 and removed again in 2.5.54. They existed only on i386 and ia64 (when built with CONFIG_HUGETLB_PAGE). In Linux 2.4.20, the syscall numbers exist,…
alarm – set an alarm clock for delivery of a signal Synopsis#include <unistd.h> unsigned int alarm(unsigned int seconds);Descriptionalarm() arranges for a SIGALRM signal to be delivered to the calling process in seconds seconds. If seconds is zero, any pending alarm is canceled. In any event any previously set alarm() is canceled. Return Valuealarm() returns the…
afs_syscall, break, fattach, fdetach, ftime, getmsg, getpmsg, gtty, isastream, lock, madvise1, mpx, prof, profil, putmsg, putpmsg, security, stty, tuxcall, ulimit, vserver – unimplemented system calls SynopsisUnimplemented system calls. DescriptionThese system calls are not implemented in the Linux kernel. Return ValueThese system calls always return -1 and set errno to ENOSYS. NotesNote that ftime(3), profil(3), and…
adjtimex, clock_adjtime, ntp_adjtime – tune kernel clock Synopsis#include <sys/timex.h> int adjtimex(struct timex *buf); int clock_adjtime(clockid_t clk_id, struct timex *buf); int ntp_adjtime(struct timex *buf);DescriptionLinux uses David L. Mills’ clock adjustment algorithm (see RFC 5905). The system call adjtimex() reads and optionally sets adjustment parameters for this algorithm. It takes a pointer to a timex structure, updates…
add_key – add a key to the kernel’s key management facility Synopsis#include <sys/types.h> #include <keyutils.h> key_serial_t add_key(const char *type, const char *description, const void *payload, size_t plen, key_serial_t keyring);No glibc wrapper is provided for this system call; see NOTES. Descriptionadd_key() creates or updates a key of the given type and description, instantiates it with the…
acct – switch process accounting on or off Synopsis#include <unistd.h> int acct(const char *filename);Feature Test Macro Requirements for glibc (see feature_test_macros(7)): acct(): Since glibc 2.21: _DEFAULT_SOURCE In glibc 2.19 and 2.20: _DEFAULT_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE < 500) Up to and including glibc 2.19: _BSD_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE < 500)DescriptionThe acct() system call enables or disables process accounting….
access, faccessat, faccessat2 – check user’s permissions for a file Synopsis#include <unistd.h> int access(const char *pathname, int mode); #include <fcntl.h> /* Definition of AT_* constants */ #include <unistd.h> int faccessat(int dirfd, const char *pathname, int mode, int flags); /* But see C library/kernel differences, below */ int faccessat2(int dirfd, const char *pathname, int mode, int…
accept, accept4 – accept a connection on a socket Synopsis#include <sys/types.h> /* See NOTES */ #include <sys/socket.h> int accept(int sockfd, struct sockaddr *addr, socklen_t *addrlen); #define _GNU_SOURCE /* See feature_test_macros(7) */ #include <sys/socket.h> int accept4(int sockfd, struct sockaddr *addr, socklen_t *addrlen, int flags);DescriptionThe accept() system call is used with connection-based socket types (SOCK_STREAM, SOCK_SEQPACKET). It…
accept, accept4 – accept a connection on a socket Synopsis#include <sys/types.h> /* See NOTES */ #include <sys/socket.h> int accept(int sockfd, struct sockaddr *addr, socklen_t *addrlen); #define _GNU_SOURCE /* See feature_test_macros(7) */ #include <sys/socket.h> int accept4(int sockfd, struct sockaddr *addr, socklen_t *addrlen, int flags);DescriptionThe accept() system call is used with connection-based socket types (SOCK_STREAM, SOCK_SEQPACKET). It…
zvbid – VBI proxy daemon Synopsiszvbid [ options ] Descriptionzvbid is a proxy for VBI devices, i.e. it forwards one or more VBI data streams to one or more connected clients and manages channel change requests. Options-dev path Path of a device from which to read data. This argument can be given several times with…
zvbi-ntsc-cc – closed caption decoder Synopsiszvbi-ntsc-cc [ options ] Descriptionzvbi-ntsc-cc reads vbi data from /dev/vbi and decodes the enclosed cc data. Start it with ‘-h’ to get a list of cmd line options. Authorstimecop [at] japan.co.jp Mike Baker <mbm [at] linux.com> Adam <adam [at] cfar.umd.edu> CopyrightThis program is free software; you can redistribute it and/or…