---
name: "SYSCALL_DEFINE3"
section: "9"
platform: "linux"
package: "linux-manual-2.6.26"
version: "2.6.26-29"
release: "Debian 5.0 (Lenny)"
platforms: ["linux"]
url: "https://new.carta.tech/SYSCALL_DEFINE3"
---

# SYSCALL\_DEFINE3(9)

send signal to one specific thread

## NAME

SYSCALL\_DEFINE3 - send signal to one specific thread

## SYNOPSIS

**SYSCALL\_DEFINE3(***tgkill***,** *int***,** *tgid***,** *int***,** *pid***,** *int***,** *sig***);**

## ARGUMENTS

*tgkill*

\-- undescribed --

*int*

\-- undescribed --

*tgid*

the thread group ID of the thread

*int*

\-- undescribed --

*pid*

the PID of the thread

*int*

\-- undescribed --

*sig*

signal to be sent

## DESCRIPTION

This syscall also checks the *tgid* and returns -ESRCH even if the PID exists but it´s not belonging to the target process anymore. This method solves the problem of threads exiting and PIDs getting reused.

## COPYRIGHT