sysinfo(2)

✨ sysinfo(2) ✨

okay bestie, welcome to sysinfo — the System Calls Manual girlie whose whole entire job is spilling the tea on your system. that's the page we're on: section 2, system calls. no cap. 💖

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🌸 NAME 🌸

sysinfo — return system information

like, it literally just hands you the receipts on your machine. 💅

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📚 LIBRARY 📚

Standard C library (libc, -lc)

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🦋 SYNOPSIS 🦋

#include <sys/sysinfo.h>

int sysinfo(struct sysinfo *info);

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👑 DESCRIPTION 👑

sysinfo() returns certain statistics on memory and swap usage, as well as the load average. it's giving "tell me everything about yourself" energy and honestly? valid. 🫶

Until Linux 2.3.16, sysinfo() returned information in the following structure:

struct sysinfo {
    long uptime;             /* Seconds since boot */
    unsigned long loads[3];  /* 1, 5, and 15 minute load averages */
    unsigned long totalram;  /* Total usable main memory size */
    unsigned long freeram;   /* Available memory size */
    unsigned long sharedram; /* Amount of shared memory */
    unsigned long bufferram; /* Memory used by buffers */
    unsigned long totalswap; /* Total swap space size */
    unsigned long freeswap;  /* Swap space still available */
    unsigned short procs;    /* Number of current processes */
    char _f[22];             /* Pads structure to 64 bytes */
};

In the above structure, the sizes of the memory and swap fields are given in bytes. got it? bytes. not vibes. bytes. 🔥

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Since Linux 2.3.23 (i386) and Linux 2.3.48 (all architectures) the structure is:

struct sysinfo {
    long uptime;             /* Seconds since boot */
    unsigned long loads[3];  /* 1, 5, and 15 minute load averages */
    unsigned long totalram;  /* Total usable main memory size */
    unsigned long freeram;   /* Available memory size */
    unsigned long sharedram; /* Amount of shared memory */
    unsigned long bufferram; /* Memory used by buffers */
    unsigned long totalswap; /* Total swap space size */
    unsigned long freeswap;  /* Swap space still available */
    unsigned short procs;    /* Number of current processes */
    unsigned long totalhigh; /* Total high memory size */
    unsigned long freehigh;  /* Available high memory size */
    unsigned int mem_unit;   /* Memory unit size in bytes */
    char _f[20-2*sizeof(long)-sizeof(int)];
                             /* Padding to 64 bytes */
};

In the above structure, sizes of the memory and swap fields are given as multiples of mem_unit bytes. so it's not raw bytes anymore bestie, it's bytes times mem_unit. do the math. 🧮✨

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💖 RETURN VALUE 💖

On success, sysinfo() returns zero. icon behavior. 🎀

On error, -1 is returned, and errno is set to indicate the error. not iconic but at least it tells you why. 😭

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🚨 ERRORS 🚨

• EFAULT — info is not a valid address. like girl, that pointer is not pointing anywhere real. 💀

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🌈 STANDARDS 🌈

Linux. that's it. that's the standard. exclusive. 💅

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📜 HISTORY 📜

Linux 0.98.pl6. ancient. vintage. a whole elder. 👑

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🍓 NOTES 🍓

All of the information provided by this system call is also available via /proc/meminfo and /proc/loadavg. so if the syscall isn't your thing, the proc filesystem has you covered. iykyk. 🌸

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🔍 SEE ALSO 🔍

• proc(5)

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and that's the whole page, bestie!! go forth and query your system. slay. periodt. 💜✨

this was brought to you by Linux man-pages 6.20, dated 2026-02-08 — mwah, love u, bye 🫶🎀