Memcpy issue on PicoW

[buhlerles]

Having an issue with memcpy on a Pico W in Arduino with Earl's core that is most puzzling (Arduino 1.8...)

memcpy appears to put the array value at the end of the segement to copy into ALL the memory locations

Code to reproduce:
uint8_t test[11] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 67, 0};
// Shift the last nine bytes one byte left.
memcpy(test, test + 1, 9);
// memcpy is putting the last value in all the array elements ??? !!!
for ( uint8_t i = 0; i < (11); i++)
{
Serial.print(test[i]);
Serial.print(" ");
}
Serial.println();

I'm anything but an expert and may be overlooking something totally basic, but the same code runs fine on a Teensy and does what you'd expect.

Any insights would be most appreciated!

[earlephilhower]

memcpy is illegal/undefined when the source and destination overlap. Use memmove.

https://man7.org/linux/man-pages/man3/memcpy.3.html

[buhlerles]

Aha - was not aware of that limitation! Thank-you!

…

On Thu, Sep 19, 2024 at 3:13 PM Earle F. Philhower, III < ***@***.***> wrote: memcpy is illegal/undefined when the source and destination overlap. Use memmove. https://man7.org/linux/man-pages/man3/memcpy.3.html — Reply to this email directly, view it on GitHub <#2482 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/APD3HIJG6BYSAHVETMHZOHDZXMO4FAVCNFSM6AAAAABOQR5JDOVHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTANRZG4YTGOA> . You are receiving this because you authored the thread.Message ID: <earlephilhower/arduino-pico/repo-discussions/2482/comments/10697138@ github.com>