what does [WEAK] mean in stm32 startup file?

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i was reading stm32f407 startup file in keil sofware to gathering some informations. i faced to this problem that what is [WEAK] symbol used?
a part of code that this symbol has been used in is :

Reset_Handler PROC
 EXPORT Reset_Handler [WEAK]
 IMPORT SystemInit
 IMPORT __main

 LDR R0, =SystemInit
 BLX R0
 LDR R0, =__main
 BX R0
 ENDP

there are more other places in the code that this symbol has been used. i just bring a part as an instance.

stm32 assembly keil

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asked 2 hours ago

Amin

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up vote
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i was reading stm32f407 startup file in keil sofware to gathering some informations. i faced to this problem that what is [WEAK] symbol used?
a part of code that this symbol has been used in is :

Reset_Handler PROC
 EXPORT Reset_Handler [WEAK]
 IMPORT SystemInit
 IMPORT __main

 LDR R0, =SystemInit
 BLX R0
 LDR R0, =__main
 BX R0
 ENDP

there are more other places in the code that this symbol has been used. i just bring a part as an instance.

stm32 assembly keil

share|improve this question

asked 2 hours ago

Amin

675

add a comment | 

up vote
1
down vote

favorite

up vote
1
down vote

favorite

i was reading stm32f407 startup file in keil sofware to gathering some informations. i faced to this problem that what is [WEAK] symbol used?
a part of code that this symbol has been used in is :

Reset_Handler PROC
 EXPORT Reset_Handler [WEAK]
 IMPORT SystemInit
 IMPORT __main

 LDR R0, =SystemInit
 BLX R0
 LDR R0, =__main
 BX R0
 ENDP

there are more other places in the code that this symbol has been used. i just bring a part as an instance.

stm32 assembly keil

share|improve this question

asked 2 hours ago

Amin

675

i was reading stm32f407 startup file in keil sofware to gathering some informations. i faced to this problem that what is [WEAK] symbol used?
a part of code that this symbol has been used in is :

Reset_Handler PROC
 EXPORT Reset_Handler [WEAK]
 IMPORT SystemInit
 IMPORT __main

 LDR R0, =SystemInit
 BLX R0
 LDR R0, =__main
 BX R0
 ENDP

there are more other places in the code that this symbol has been used. i just bring a part as an instance.

stm32 assembly keil

stm32 assembly keil

share|improve this question

asked 2 hours ago

Amin

675

share|improve this question

asked 2 hours ago

Amin

675

share|improve this question

share|improve this question

asked 2 hours ago

Amin

675

asked 2 hours ago

Amin

675

asked 2 hours ago

Amin

675

675

add a comment | 

add a comment | 

1 Answer
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It says the implementation of the function should be weakly linked (as opposed to strongly linked, which is the usual).

This allows providing a "fallback" implementation of a function, in case no other (strongly linked) is found.

This is often used for default interrupt handlers in bare-metal MCU frameworks. This way, when you implement an interrupt, you just have to write your function, without having to remove the default one from the sources, and the linker does the job.

See https://en.m.wikipedia.org/wiki/Weak_symbol

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answered 2 hours ago

dim

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1 Answer
1

active

oldest

votes

1 Answer
1

active

oldest

votes

active

oldest

votes

active

oldest

votes

up vote
4
down vote



accepted

It says the implementation of the function should be weakly linked (as opposed to strongly linked, which is the usual).

This allows providing a "fallback" implementation of a function, in case no other (strongly linked) is found.

This is often used for default interrupt handlers in bare-metal MCU frameworks. This way, when you implement an interrupt, you just have to write your function, without having to remove the default one from the sources, and the linker does the job.

See https://en.m.wikipedia.org/wiki/Weak_symbol

share|improve this answer

answered 2 hours ago

dim

12.6k22263

add a comment | 

up vote
4
down vote



accepted

It says the implementation of the function should be weakly linked (as opposed to strongly linked, which is the usual).

This allows providing a "fallback" implementation of a function, in case no other (strongly linked) is found.

This is often used for default interrupt handlers in bare-metal MCU frameworks. This way, when you implement an interrupt, you just have to write your function, without having to remove the default one from the sources, and the linker does the job.

See https://en.m.wikipedia.org/wiki/Weak_symbol

share|improve this answer

answered 2 hours ago

dim

12.6k22263

add a comment | 

up vote
4
down vote



accepted

up vote
4
down vote



accepted

It says the implementation of the function should be weakly linked (as opposed to strongly linked, which is the usual).

This allows providing a "fallback" implementation of a function, in case no other (strongly linked) is found.

This is often used for default interrupt handlers in bare-metal MCU frameworks. This way, when you implement an interrupt, you just have to write your function, without having to remove the default one from the sources, and the linker does the job.

See https://en.m.wikipedia.org/wiki/Weak_symbol

share|improve this answer

answered 2 hours ago

dim

12.6k22263

It says the implementation of the function should be weakly linked (as opposed to strongly linked, which is the usual).

This allows providing a "fallback" implementation of a function, in case no other (strongly linked) is found.

This is often used for default interrupt handlers in bare-metal MCU frameworks. This way, when you implement an interrupt, you just have to write your function, without having to remove the default one from the sources, and the linker does the job.

See https://en.m.wikipedia.org/wiki/Weak_symbol

share|improve this answer

answered 2 hours ago

dim

12.6k22263

share|improve this answer

share|improve this answer

answered 2 hours ago

dim

12.6k22263

answered 2 hours ago

dim

12.6k22263

answered 2 hours ago

dim

12.6k22263

12.6k22263

add a comment | 

add a comment | 

 

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