---
name: "sdrstring"
section: "3"
platform: "linux"
package: "ion-doc"
version: "3.2.1+dfsg-1.1"
release: "Debian 9 (Stretch)"
platforms: ["linux"]
url: "https://new.carta.tech/sdrstring"
---

# sdrstring(3)

Simple Data Recorder string functions

## NAME

sdrstring - Simple Data Recorder string functions

## SYNOPSIS

```
    #include "sdr.h"
    Object sdr_string_create (Sdr sdr, char *from);
    Object sdr_string_dup    (Sdr sdr, Object from);
    int    sdr_string_length (Sdr sdr, Object string);
    int    sdr_string_read   (Sdr sdr, char *into, Object string);
```

## DESCRIPTION

SDR strings are used to record strings of up to 255 ASCII characters in the heap space of an SDR.  Unlike standard C strings, which are terminated by a zero byte, SDR strings record the length of the string as part of the string object.

To store strings longer than 255 characters, use *sdr\_malloc()* and *sdr\_write()* instead of these functions.

- Object sdr\_string\_create(Sdr sdr, char \*from)

  Creates a "self-delimited string" in the heap of the indicated SDR, allocating the required space and copying the indicated content.  *from* must be a standard C string for which *strlen()* must not exceed 255; if it does, or if insufficient SDR space is available, 0 is returned.  Otherwise the address of the newly created SDR string object is returned.  To destroy, just use *sdr\_free()*.

- Object sdr\_string\_dup(Sdr sdr, Object from)

  Creates a duplicate of the SDR string whose address is *from*, allocating the required space and copying the original string's content.  If insufficient SDR space is available, 0 is returned.  Otherwise the address of the newly created copy of the original SDR string object is returned.  To destroy, use *sdr\_free()*.

- int sdr\_string\_length(Sdr sdr, Object string)

  Returns the length of the indicated self-delimited string (as would be returned by *strlen()*), or -1 on any error.

- int sdr\_string\_read(Sdr sdr, char \*into, Object string)

  Retrieves the content of the indicated self-delimited string into memory as a standard C string (NULL terminated).  Length of *into* should normally be SDRSTRING\_BUFSZ (i.e., 256) to allow for the largest possible SDR string (255 characters) plus the terminating NULL.  Returns length of string (as would be returned by *strlen()*), or -1 on any error.

## SEE ALSO

[*sdr*(3)](/sdr/3.md), [*sdrlist*(3)](/sdrlist/3.md), [*sdrtable*(3)](/sdrtable/3.md), [*string*(3)](/string/3.md)