BARRIER(3PVM)

💖 BARRIER(3PVM) — the pvm_barrier page, but make it make sense 💖

okay bestie, welcome to PVM Version 3.4 — this is pvm_barrier, from the 3PVM manual, and it's literally the group-chat "wait for everyone to show up before we start" function. no cap. 🫶

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✨ NAME ✨

pvm_barrier — blocks the calling process until all processes in a group have called it.

like. it just waits. iconic behaviour honestly. 💅

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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 calling process has to actually be a member of it. no lurking, you gotta be in the gc. 💜
• count — an integer saying how many group members have to call pvm_barrier before they all get released. it's not required required, but count is expected to be the total number of members of the specified group. like, the whole squad. 🌈
• info — the integer status code the routine hands back. anything less than zero means something went wrong. 😭

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🦋 DESCRIPTION 🦋

so the routine pvm_barrier blocks the calling process until count members of the group have called pvm_barrier. that's the whole vibe. 🧚

now, why is count even a thing, you ask? because processes could be joining the given group after other processes have already called pvm_barrier. which means PVM genuinely doesn't know how many group members to wait for at any given instant. the math isn't mathing, so you have to tell it. 🙈

count can be set lower, sure, but it's typically the total number of members of the group. so the logical function of the pvm_barrier call is to provide a group synchronization. everybody touches grass at the same time. ⭐

during any given barrier call, all participating group members must call barrier with the same count value. same number, bestie. don't be the one person who breaks the group chat. 💀

once a given barrier has been successfully passed, pvm_barrier can be called again by the same group using the same group name. it's re-usable, it's sustainable, it's giving main character energy. 👑

if pvm_barrier is successful, info will be 0. if some error occurs then info will be < 0.

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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 )

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💅 ERRORS 💅

these error conditions can be returned by pvm_barrier:

• PvmSysErr — pvmd was not started or has crashed. the daemon ghosted you. 💀
• PvmBadParam — giving a count < 1. like girl, that's not a count, that's nothing. 😭
• PvmNoGroup — giving a non-existent group name. you tried to @ a group that doesn't exist. 🫶
• PvmNotInGroup — calling process is not in specified group. you're in the server but not in the channel. 🙈

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🌟 SEE ALSO 🌟

• pvm_joingroup(3PVM) — go read it, it's the pre-req, it's the lore. 📖

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okay that's the whole page, slay. this was BARRIER(3PVM) from PVM Version 3.4, dated 30 August, 1993 — yes, the original is vintage, and vintage is literally always iconic. ✨ bye bestie, go synchronize your group 🎀💖