From Newsgroup: comp.lang.c

One of many newbie questions from me... Cant find the info I'm looking for.

If SIG_IGN is an acronym for signal ignore, then what does DFL mean?
I've know (well I presume) it restores default behavior, but the acronym?
--
:wq
Mike Sanders
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From Newsgroup: comp.lang.c

On Sat, 08 Nov 2025 19:01:00 +0000, Michael Sanders wrote:

One of many newbie questions from me... Cant find the info I'm looking for.

If SIG_IGN is an acronym for signal ignore, then what does DFL mean?
I've know (well I presume) it restores default behavior, but the acronym?

From the C11 draft standard (yes, I know, but that's the most current I have)

7.14.1.1 The signal function
2. ... If the value of func is SIG_DFL, default handling for that
signal will occur.

Neither the C standard, nor the Posix standards or Unix manuals before that, seem to specify exactly _why_ SIG_DFL is named that way. Presumably because other abbreviations would somehow conflict or possibly be confused with existing nomenclature (SIGUSR1 and SIGUSR2, for instance, are user-DEFined signals, and SIG_DEF might confuse someone who isn't entirely familiar with
the nomenclature), or because (like many abbreviations in Unix, "DeFauLt"
made more sense to someone.
--
Lew Pitcher
"In Skills We Trust"
Not LLM output - I'm just like this.
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From Newsgroup: comp.lang.c

On Sat, 8 Nov 2025 19:28:20 -0000 (UTC), Lew Pitcher wrote:

On Sat, 08 Nov 2025 19:01:00 +0000, Michael Sanders wrote:

One of many newbie questions from me... Cant find the info I'm looking for. >>
If SIG_IGN is an acronym for signal ignore, then what does DFL mean?
I've know (well I presume) it restores default behavior, but the acronym?

From the C11 draft standard (yes, I know, but that's the most current I have)

7.14.1.1 The signal function
2. ... If the value of func is SIG_DFL, default handling for that
signal will occur.

Neither the C standard, nor the Posix standards or Unix manuals before that, seem to specify exactly _why_ SIG_DFL is named that way. Presumably because other abbreviations would somehow conflict or possibly be confused with existing nomenclature (SIGUSR1 and SIGUSR2, for instance, are user-DEFined signals, and SIG_DEF might confuse someone who isn't entirely familiar with the nomenclature), or because (like many abbreviations in Unix, "DeFauLt" made more sense to someone.

Thanks again Lew. I'm running with: [D]e[F]ault [L]evel in my // comments.
--
:wq
Mike Sanders
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From Newsgroup: comp.lang.c

On 2025-11-08, Lew Pitcher <lew.pitcher@digitalfreehold.ca> wrote:

On Sat, 08 Nov 2025 19:01:00 +0000, Michael Sanders wrote:

One of many newbie questions from me... Cant find the info I'm looking for. >>
If SIG_IGN is an acronym for signal ignore, then what does DFL mean?
I've know (well I presume) it restores default behavior, but the acronym?

From the C11 draft standard (yes, I know, but that's the most current I have)

7.14.1.1 The signal function
2. ... If the value of func is SIG_DFL, default handling for that
signal will occur.

Neither the C standard, nor the Posix standards or Unix manuals before that, seem to specify exactly _why_ SIG_DFL is named that way.

It's not named SIGNAL_DEFAULT probably in order to harmonize with
strpbrk, which is not named string_pointer_to_break.

Programmers long ago loved creating "bumper stumpers" by removing
vowels and some consontants too.

I agree with them; I positively never want to write shit like

#include <standard_input_ouput.header>

or work in any tech stack where that is the norm.

The superfluous "std" should have been omitted from <stdio.h>; other
standard headers do not carry a reminder that they are standard, like <string.h>, <math.h> or <assert.h>.
--
TXR Programming Language: http://nongnu.org/txr
Cygnal: Cygwin Native Application Library: http://kylheku.com/cygnal
Mastodon: @Kazinator@mstdn.ca
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From Newsgroup: comp.lang.c

On 11/8/2025 12:14 PM, Kaz Kylheku wrote:

On 2025-11-08, Lew Pitcher <lew.pitcher@digitalfreehold.ca> wrote:

On Sat, 08 Nov 2025 19:01:00 +0000, Michael Sanders wrote:

One of many newbie questions from me... Cant find the info I'm looking for. >>>
If SIG_IGN is an acronym for signal ignore, then what does DFL mean?
I've know (well I presume) it restores default behavior, but the acronym? >>

From the C11 draft standard (yes, I know, but that's the most current I have)

7.14.1.1 The signal function
2. ... If the value of func is SIG_DFL, default handling for that >> signal will occur.

Neither the C standard, nor the Posix standards or Unix manuals before that, >> seem to specify exactly _why_ SIG_DFL is named that way.

It's not named SIGNAL_DEFAULT probably in order to harmonize with
strpbrk, which is not named string_pointer_to_break.

Programmers long ago loved creating "bumper stumpers" by removing
vowels and some consontants too.

:^)

lol. For some reason it reminds me of the PPC instruction, EIEIO. ;^)

I agree with them; I positively never want to write shit like

#include <standard_input_ouput.header>

or work in any tech stack where that is the norm.

The superfluous "std" should have been omitted from <stdio.h>; other standard headers do not carry a reminder that they are standard, like <string.h>, <math.h> or <assert.h>.

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From Newsgroup: comp.lang.c

On 2025-11-08, Michael Sanders <porkchop@invalid.foo> wrote:

On Sat, 8 Nov 2025 19:28:20 -0000 (UTC), Lew Pitcher wrote:

On Sat, 08 Nov 2025 19:01:00 +0000, Michael Sanders wrote:

One of many newbie questions from me... Cant find the info I'm looking for. >>>
If SIG_IGN is an acronym for signal ignore, then what does DFL mean?
I've know (well I presume) it restores default behavior, but the acronym? >>

From the C11 draft standard (yes, I know, but that's the most current I have)

7.14.1.1 The signal function
2. ... If the value of func is SIG_DFL, default handling for that >> signal will occur.

Neither the C standard, nor the Posix standards or Unix manuals before that, >> seem to specify exactly _why_ SIG_DFL is named that way. Presumably because >> other abbreviations would somehow conflict or possibly be confused with
existing nomenclature (SIGUSR1 and SIGUSR2, for instance, are user-DEFined >> signals, and SIG_DEF might confuse someone who isn't entirely familiar with >> the nomenclature), or because (like many abbreviations in Unix, "DeFauLt"
made more sense to someone.

Thanks again Lew. I'm running with: [D]e[F]ault [L]evel in my // comments.

That is likely apocryphal; since L is present in "default", the
simplest hypothesis is that the L in DFL is that one.

The argument in question is a handler not a level. That has an L,
but not in the leading position, making the revised origin hypothesis [D]e[F]ault hand[L]ing is even more farfetched.
--
TXR Programming Language: http://nongnu.org/txr
Cygnal: Cygwin Native Application Library: http://kylheku.com/cygnal
Mastodon: @Kazinator@mstdn.ca
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From Newsgroup: comp.lang.c

On Sat, 8 Nov 2025 20:17:28 -0000 (UTC), Kaz Kylheku wrote:

Thanks again Lew. I'm running with: [D]e[F]ault [L]evel in my // comments.

That is likely apocryphal; since L is present in "default", the
simplest hypothesis is that the L in DFL is that one.

The argument in question is a handler not a level. That has an L,
but not in the leading position, making the revised origin hypothesis [D]e[F]ault hand[L]ing is even more farfetched.

Yeah my take adds a word which is less than optimal...
--
:wq
Mike Sanders
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From Newsgroup: comp.lang.c

Michael Sanders <porkchop@invalid.foo> writes:

One of many newbie questions from me... Cant find the info I'm looking for.

If SIG_IGN is an acronym for signal ignore, then what does DFL mean?
I've know (well I presume) it restores default behavior, but the acronym?

It never would have occurred to me that SIG_DFL was anything other
than an abbreviation for SIGnal_DeFauLt.

It's clear enough that SIG_ERR means SIGnal_ERRor, and SIG_IGN
means SIGnal_IGNore. SIG_DFL follows the same pattern of SIG_XXX,
but doesn't take the first three letters of the word it abbreviates
-- probably because DEF suggests "definition" rather than "default".

There are plenty of cases where C identifiers are abbreviations not
taken from the first letters of a word. See strcmp (STRing CoMPare),
sqrt (SQuare RooT), etc.

(Pedantic quibble: It's not really an acronym, which is a word formed
from the initials of several words, like laser, radar, or scuba).
--
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
void Void(void) { Void(); } /* The recursive call of the void */
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