STRCAT not working when sending data from nrf52840 and no response in the apps.

RE: STRCAT not working when sending data from nrf52840 and no response in the apps.

ox00 — Wed, 20 Nov 2019 10:42:19 GMT

snprintf(buf,42, "A%dBBCCDDEEAABBCCDDEEAABBCCDDEEAABBCCDDXX", i);
// puts string into buffer

use this function to concatenate the string.

RE: STRCAT not working when sending data from nrf52840 and no response in the apps.

ox00 — Thu, 14 Nov 2019 02:50:44 GMT

You are so helpful Simon. Thanks bro!

RE: STRCAT not working when sending data from nrf52840 and no response in the apps.

Simon — Wed, 13 Nov 2019 23:16:04 GMT

This is because a[] is not large enough to contain the concatenated resulting string, see the documentation. It should be large enough to store the initial string in addition to the string to be appended.

I tried to experiment and figured out that the following:

uint8_t a[]="A1BBCCDDEEAABBCCDDEEAABBCCDDEEAABBCCDDEE";
uint8_t test[]="XXX123";
strcat(a, test);
NRF_LOG_INFO("a[]: %s",a);

Gave the following output:

<info> app: a[]: A1BBCCDDEEAABBCCDDEEAABBCCDDEEAABBCCDDEEXXX123

This is because the strcat operation will write outside a[]. However, you should not rely on this and you should set the size of a[] when you define it. Read why on this thread.

Best regards,

Simon

Best regards,

Simon