---
name: "mst_findmatch"
section: "3"
platform: "linux"
package: "libmseed-doc"
version: "2.19.8-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/mst_findmatch"
---

# mst\_findmatch(3)

Searching a MSTraceGroup for specific MSTrace structures.

## NAME

mst\_findmatch - Searching a MSTraceGroup for specific MSTrace structures.

## SYNOPSIS

```
#include <libmseed.h>
MSTrace  *mst_findmatch ( MSTrace *startmst, char dataquality,
                          char *network, char *station,
                          char *location, char *channel );
MSTrace  *mst_findadjacent ( MSTraceGroup *mstg,
                             flag *whence, char dataquality,
                             char *network, char *station,
                             char *location, char *channel,
                             double samprate, double sampleratetol,
                             hptime_t starttime, hptime_t endtime,
                             double timetol);
```

## DESCRIPTION

**mst\_findmatch** traverses a MSTrace chain starting at *startmst* and returns the first entry that matches the source name identifiers.  If *dataquality* is not zero it must also match the found entry.  A calling program commonly calls this routine in a loop in order to find all matching MSTraces in a MSTraceGroup.

**mst\_findadjacent** finds the first entry in the MSTraceGroup pointed to by *mstg* that matches the given source name identifiers and is time adjacent to the time coverage described by the *samprate*, *starttime* and *endtime*.  If *dataquality* is not zero it must also match the found entry.  See **[ms\_time(3)](/ms_time/3.md)** for a description of the high precision epoch time format needed for *starttime* and *endtime*.

The tolerance for sample rate and time matching can also be specified. If *sampratetol* is -1.0 the default tolerance of abs(1-sr1/sr2) \< 0.0001 is used.  If *timetol* is -1.0 the default time tolerance of 1/2 the sample period will be used.  If *sampratetol* or *timetol* is -2.0 the respective tolerance check will not be performed.  If time tolerance is not checked *whence* will be set to whichever end fits best.  The time tolerance is specified in seconds.

When an adjacent MSTrace is found the *whence* flag will be set to indicate where the indicated time span is adjacent in the following way:

```
1: time span fits at the end of the MSTrace
2: time span fits at the beginning of the MSTrace
```

## RETURN VALUES

**mst\_findmatch** returns a pointer to the matching MSTrace structure  or 0 if no match found or error.

**mst\_findadjacent** returns a pointer to the adjacent MSTrace structure and the *whence* flag is set when an adjacent MSTrace is found or 0 when no adjacent MSTrace is found.

## SEE ALSO

**[ms\_intro(3)](/ms_intro/3.md)**, **[mst\_init(3)](/mst_init/3.md)** and **[ms\_time(3)](/ms_time/3.md)**.

## AUTHOR

```
Chad Trabant
IRIS Data Management Center
```