BARRIER(3PVM)

💖 BARRIER 💖

okay bestie, gather round, because this is the manual page for pvm_barrier from PVM Version 3.4, and it's giving "group project but make it actually work" energy. 🫶

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✨ NAME ✨

pvm_barrier — blocks the calling process until all processes in a group have called it. yes, it's a group chat read receipt. nobody moves until everyone's typed "here". 💅

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🌸 SYNOPSIS 🌸

C:

int info = pvm_barrier( char *group, int count )

Fortran:

call pvmfbarrier( group, count, info )

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🎀 PARAMETERS 🎀

• group — a character string with the group name. the group has to exist, and the process calling this has to be a member of it. no lurking in the group chat you're not in, bestie. 🚫
• count — an integer saying how many group members have to call pvm_barrier before they all get released. it's not required to be this, but count is expected to be the total number of members of the specified group.
• info — the integer status code this routine hands back to you. anything less than zero? that's an error, babe. 😭

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🦋 DESCRIPTION 🦋

so pvm_barrier blocks the calling process until count members of the group have called pvm_barrier. the count argument is literally required because processes could be joining the given group after other processes have already called pvm_barrier. like, PVM genuinely doesn't know how many group members to wait for at any given instant. 👀 although count can be set less, it is typically the total number of members of the group. so the logical function of the pvm_barrier call is to provide a group synchronization. periodt.

during any given barrier call, all participating group members must call barrier with the same count value. no mismatched numbers, that's not it. once a given barrier has been successfully passed, pvm_barrier can be called again by the same group using the same group name. 💖

if pvm_barrier is successful, info will be 0. if some error occurs then info will be < 0. that's the whole vibe check right there.

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🌈 EXAMPLES 🌈

C:

inum = pvm_joingroup( "worker" );
        .
        .
info = pvm_barrier( "worker", 5 );

Fortran:

CALL PVMFJOINGROUP( "shakers", INUM )
COUNT = 10
CALL PVMFBARRIER( "shakers", COUNT, INFO )

look at them go. iconic. 🔥

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💀 ERRORS 💀

these error conditions can be returned by pvm_barrier:

• PvmSysErr — pvmd was not started or has crashed. the whole thing ghosted you. 💀
• PvmBadParam — giving a count < 1. not me passing a zero 💀
• PvmNoGroup — giving a non-existent group name. that group does NOT exist, bestie, stop trying to join it. 🙈
• PvmNotInGroup — calling process is not in specified group. you're not on the list. 😭

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👑 SEE ALSO 👑

• pvm_joingroup(3PVM)

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and that's the whole page, no cap. this was PVM Version 3.4, dated 30 August, 1993 — yeah, she's a vintage queen and she still serves. mwah. 💅✨🎀