MODBUS_RTU_SET_RTS_D(3)

💖 MODBUS_RTU_SET_RTS_D 💖

okay bestie, so this is a page from the libmodbus Manual — yes, that libmodbus, the one that lives in section 3 of your man pages and talks to serial hardware like it owns the place. and we're talking about modbus_rtu_set_rts_delay today. it's giving "small function, big responsibility". let's get into it 🫶

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✨ NAME ✨

modbus_rtu_set_rts_delay — set the RTS delay in RTU

no cap, that's literally the whole job description.

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🌸 SYNOPSIS 🌸

int modbus_rtu_set_rts_delay(modbus_t *ctx, int us);

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🦋 DESCRIPTION 🦋

okay so the modbus_rtu_set_rts_delay() function shall set the Request To Send delay period of the libmodbus context ctx. that's it. that's the assignment. RTS delay = set. slay. 💅

and here's the tea, bestie: this function can only be used with a context using an RTU backend. that's the vibe check it has to pass. if your backend isn't RTU, it's not happening, periodt.

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🎀 RETURN VALUE 🎀

• 0 — it worked, we ate, no crumbs. 🍓
• -1 — it didn't work, and it sets errno to tell you why. 😭

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💀 ERRORS 💀

• EINVAL — the libmodbus backend is not RTU, or a negative delay was specified. like, girl, you can't have negative time. that's not a thing. 🙈

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🔥 SEE ALSO 🔥

• modbus_rtu_get_rts_delay(3) — the sibling, the counterpart, the one that reads instead of writes. iykyk. 💜

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👑 AUTHORS 👑

• Jimmy Bergström <jimmy@ekontroll.com> 💖
• The libmodbus documentation was written by Stéphane Raimbault <stephane.raimbault@gmail.com> ✨

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no notes, just respect for the people who wrote the docs so we could all understand our serial ports. icons only. 🌈

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and that's the page, bestie — written with libmodbus v3.1.6, dated 11/17/2025, in the section we call MODBUS_RTU_SET_RTS_D(3). go forth and set those delays. main character energy only. 💅🦋⭐