'\" t
.\" Title: modbus_read_input_registers
.\" Author: [see the "AUTHORS" section]
.\" Generator: DocBook XSL Stylesheets vsnapshot
.\" Date: 10/15/2022
.\" Manual: libmodbus Manual
.\" Source: libmodbus v3.1.6
.\" Language: English
.\"
.TH "MODBUS_READ_INPUT_RE" "3" "10/15/2022" "libmodbus v3\&.1\&.6" "libmodbus Manual"
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.SH "NAME"
modbus_read_input_registers \- read many input registers
.SH "SYNOPSIS"
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\fBint modbus_read_input_registers(modbus_t *\fR\fB\fIctx\fR\fR\fB, int \fR\fB\fIaddr\fR\fR\fB, int \fR\fB\fInb\fR\fR\fB, uint16_t *\fR\fB\fIdest\fR\fR\fB);\fR
.SH "DESCRIPTION"
.sp
The \fBmodbus_read_input_registers()\fR function shall read the content of the \fInb\fR input registers to address \fIaddr\fR of the remote device\&. The result of the reading is stored in \fIdest\fR array as word values (16 bits)\&.
.sp
You must take care to allocate enough memory to store the results in \fIdest\fR (at least \fInb\fR * sizeof(uint16_t))\&.
.sp
The function uses the Modbus function code 0x04 (read input registers)\&. The holding registers and input registers have different historical meaning, but nowadays it\(cqs more common to use holding registers only\&.
.SH "RETURN VALUE"
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The function shall return the number of read input registers if successful\&. Otherwise it shall return \-1 and set errno\&.
.SH "ERRORS"
.PP
\fBEMBMDATA\fR
.RS 4
Too many bits requested
.RE
.SH "SEE ALSO"
.sp
\fBmodbus_read_input_bits\fR(3) \fBmodbus_write_register\fR(3) \fBmodbus_write_registers\fR(3)
.SH "AUTHORS"
.sp
The libmodbus documentation was written by Stéphane Raimbault